A projection optical system is disclosed with which undistorted images can be obtained at any image position within a specification range, and whose projection angle can be changed. The projection optical system includes a plurality of optical elements and a first optical system constituted by at least one of the plurality of optical elements having the ability to form an image with light onto a predetermined surface different from the projection surface. A projection image of the original image can be moved by rotating a first optical element of the plurality of optical elements substantially around a center of an exit pupil position of the first optical system as the rotation center.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A projection optical system projecting light from an original image onto a projection surface, comprising: a plurality of optical elements, wherein a first optical system is constituted by at least one of the plurality of optical elements and has an ability to form an image of the original image on a predetermined surface different from the projection surface; and wherein a first optical element of the plurality of optical elements is rotated substantially around a center of an exit pupil of the first optical system, such that a projection image of the original image is moved.
2. The projection optical system according to claim 1 , wherein the first optical element is rotated around a point on an optical axis of the first optical system, the point being substantially at a position of the exit pupil of the first optical system.
3. The projection optical system according to claim 1 , wherein the movement of the projection image is at least one of a parallel movement and a movement in a tilting direction.
4. The projection optical system according to claim 1 , wherein the first optical system has an ability to image the light from the original image onto a spherical surface whose curvature center is a point on an optical axis of the first optical system, the center point being substantially at a position of the exit pupil of the first optical system.
5. The projection optical system according to claim 1 , wherein the exit pupil of the first optical system is formed at a position closer to the projection surface than an optical element, which is closest to the projection surface, of the first optical system.
6. The projection optical system according to claim 1 , wherein a second optical system is constituted by at least one of the plurality of optical elements and is arranged at a position closer to the projection surface than the first optical system; and wherein the second optical system comprises a curved reflective surface.
7. The projection optical system according to claim 6 , wherein the second optical system comprises a curved and rotationally asymmetric reflective surface.
8. The projection optical system according to claim 6 , wherein the second optical system forms an intermediate image of the original image at a position which is different from the projection surface.
9. The projection optical system according to claim 8 , wherein the intermediate image is formed at a position closer to the original image than the reflective surface, which is closest to the projection surface, of the second optical system.
10. The projection optical system according to claim 8 , wherein the second optical system comprises a plurality of curved reflective surfaces; and wherein the intermediate image is formed between a first reflective surface which is closest to the projection surface side, and a second reflective surface which is the second one counting from the projection surface side, of the curved reflective surfaces.
11. The projection optical system according to claim 6 , wherein the second optical system comprises four curved reflective surfaces.
12. The projection optical system according to claim 6 , wherein the reflective surface, which is closest to the projection surface, of the second optical system is a concave surface.
13. The projection optical system according to claim 6 , wherein all reflective surfaces of the second optical system are curved and rotationally asymmetric surfaces.
14. The projection optical system according to claim 6 , wherein the second optical system is rotated around a point on an optical axis of the first optical system, the point being substantially at a position of the exit pupil of the first optical system.
15. The projection optical system according to claim 6 , wherein the first optical element is arranged between the first optical system and the second optical system.
16. The projection optical system according to claim 15 , wherein the first optical element is rotatable in a plurality of rotational directions around a point, the point being on an optical axis of the first optical system.
17. The projection optical system according to claim 15 , wherein the first optical element is a reflective member.
18. The projection optical system according to claim 15 , wherein a second optical element of the plurality of optical element is rotated substantially around a center of an exit pupil of the first optical system, the first optical element and the second optical element are rotatable optical elements being rotatable in different directions.
19. The projection optical system according to claim 18 , wherein the second optical element is a reflective member.
20. The projection optical system according to claim 6 , further comprising an optical deflection element arranged between the first optical system and the second optical system, the optical deflection element deflecting a light ray traveling on the optical axis of the first optical system.
21. The projection optical system according to claim 1 , wherein the projection optical system projects the light from the original image obliquely onto the projection surface.
22. The projection optical system according to claim 1 , wherein a center line of light reaching a center of the projection image from a center of the original image is tilted with respect to the projection surface.
23. The projection optical system according to claim 1 , wherein the first optical system comprises a coaxial and rotationally symmetric lens.
24. The projection optical system according to claim 1 , wherein the first optical system consists of coaxial and rotationally symmetric lenses.
25. The projection optical system according to claim 1 , wherein the projection surface is a substantially planar surface.
26. The projection optical system according to claim 1 , wherein the projection optical system projects light from a plurality of original images onto the projection surface; and wherein the projection optical system further comprises a color combining optical system which combines the light from the plurality of original images, the color combining optical system being arranged at a position closer to the original image than the first optical system.
27. An image projection apparatus comprising: an image forming element forming an original image; and the projection optical system according to claim 1 .
28. The image projection apparatus according to claim 27 , wherein the image forming element is one of a reflective liquid crystal display element, a transmissive liquid crystal display element, and a mirror device.
29. An image display system comprising: the image projection apparatus according to claim 27 ; and an image information supply apparatus supplying image information for forming the original image with the image forming element to the image projection apparatus.
30. The projection optical system according to claim 1 , wherein the first optical element is arranged at the exit pupil position of the first optical system.
31. A projection optical system projecting light from an original image onto a projection surface, comprising: a first optical system having an ability to form an image with the light onto a surface different from the projection surface; a second optical system guiding light from the first optical system toward the projection surface and forming a projection image of the original image on the projection surface; and an optical element arranged between the first and the second optical systems, wherein at least one of the first and the second optical systems and the optical element is rotated substantially around a center of an exit pupil of the first optical system, such that the projection image on the projection surface is moved.
32. The projection optical system according to claim 31 , wherein the optical element is a plane mirror arranged substantially at the exit pupil of the first optical system, and wherein the optical element is rotated substantially around the center of the exit pupil of the first optical system, such that the projection image on the projection surface is moved.
33. The projection optical system according to claim 31 , wherein the second optical system comprises at least a rotationally asymmetric reflective surface.
34. An image projection apparatus comprising: an image forming element forming an original image; and a projection optical system projecting light from the original image onto a projection surface, wherein the projection optical system includes, a first optical system having an ability to form an image with the light onto a surface different from the projection surface; a second optical system guiding light from the first optical system toward the projection surface and forming a projection image of the original image on the projection surface; and an optical element arranged between the first and the second optical systems, wherein at least one of the first and the second optical systems and the optical element is rotated substantially around a center of an exit pupil of the first optical system, such that the projection image on the projection surface is moved.
35. An image display system comprising: the image projection apparatus according to claim 34 ; and an image information supply apparatus supplying image information for forming the original image with the image forming element to the image projection apparatus.
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February 2, 2006
August 7, 2007
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